1. Field of the Invention:
The present invention relates to devices and methods for determining physical properties of a conductive fluid. More particularly, the present invention relates to determining the viscosity and specific gravity of molten glass, particularly glass used for encapsulating wastes.
2. Discussion of Background:
Devices and methods for measuring physical properties of electrically conductive fluids such as molten glass are well known. The prior art includes measurement techniques for determining density, specific gravity, and conductivity (or resistivity) of various kinds of fluids, including the constituents added to make glass in a melter.
In U.S. Pat. No. 4,871,000, Ritter describes a method for continually measuring the depth of radioactive glass melt flowing into a mold. The method is based on the electrical resistivity of the glass melt.
Another U.S. Pat. No. 4,422,326 issued to Sasaki, describes a method for measuring density and depth of a glass melt that includes radioactive constituents. Sasaki uses a bubble-type level measuring method to find the minimum pressures required for releasing bubbles into the fluid for density and depth measurements.
Similarly, Baumert, in U.S. Pat. No. 4,359,211, describes the use of bubbles in metallurgical melts for determining the level of a slag layer in a melt. He mentions, but does not describe, determination of melt viscosity and consistency.
In U.S. Pat. No. 2,933,094, Cunniff, et al uses a Wheatstone bridge to determine concentrations of the contents, specific gravity and conductivity of a pickling solution.
Despite the numerous methods and devices existing in the prior art for determining various physical parameters of fluids such as molten glass, since glass quality, especially glass encapsulating waste, is determined by its physical characteristics, there is a need for an accurate method and device for determining the viscosity.